Crossover protection apparatus



Malch 10, 1953 1 B. YARBROUGH 2,631,227

CROSSOVER PROTECTION APPARATUS Filed May 21, 194e 2 SHEETSQSHEET 1 FMH". 355# Heel 4 4 Heel N115' Signal Caml/10! '.INVENTOR.

Lowe .'lznbpazfyjz.

March 10 1953 L. B. YARBROUGH CROSSOVER PROTECTION APPARATUS Filed May 21, 1946 INVENTOR. Lowe! .Yanbzazggh HJSATTIZNEK Patented Mar. l0, 1953 CROSS OVER PROTECTION APPARATUS Lowell B. Yarbrough, Decatur, Ill., assignor to Westinghouse Air Brake Company, a corporation of Pennsylvania Application May 21, 1946, Serial No. 671,191

(Cl. l24S-414) 14 Claims. yl

My invention relates to traffic protection apparatus, and particularly to l'apparatus for providing crossover protection -i'or trains moving along railway tracks which are connected with each other by a crossover 'track 'through handoperated track switches.

A requisite for crossover protection apparatus is that it must be so arranged that 'a car or locomotive, while occupying .a crossover such for example as one connecting two main tracks, while the switches vare in the normal position for train movements along lthe main tracks, will `cause a signal for each main track to indicate stop if the car or locomotive is within fouling distance of that main track. In crossover protection schemes embodying track circuits. one characteristic should therefore be high shunting sensitivity in order to insure that the crossover track circuits will be shunted if the crossover .track has high contact resistance due to infrequency of train movements over the crossover. Also, in crossover protection schemes embodying track circuits, as nearly as possible every portion of the track rails should be connected in series -in the track circuits in order to provide the maximum broken rail protection. Protection against defective insulated joints should also be provided.

One feature of my invention is the provision of improved shunting sensitivity through determination of the condition of occupancy of a crossover track by the picking up of a track relay instead of by release of a track relay.

Another feature of my invention is the provision of means for increasing the pick-up length of the crossover track circuit section while the track relay is deenergized.

I shall describe two forms of apparatus embodying my invention, and shall then point out the novel features thereof in claims.

n the accompanying drawings, Fig. l is a diagrammatic view showing one form of apparatus embodying my invention, in which one normally deenergized track circuit is provided for a crossover track and is arranged to become energized only when the switches are restored to the normal position and the crossover track isk unoccupied, and for only a brief period of time; and Fig. 2 is a diagrammatic view showing a modified form of the apparatus of Fig. 1, in which a crossover track is provided with two track circuits each of which is arranged to become energized only when the adjacent switch is in the normal position and the corresponding track section is unoccupied, and each of which is lengthened by a jumper its track relay is deenergized.

Similar reference characters refer tosimilar parts in each ofthe views.

Referring liirst `vto Fig. 1, 'a stretch iof railway is shown comprising two :main tracks designated. by the reference characters IT and 2T, connected with each other by a crossover track designated by the reference character 3T, through yhand-- operated switches IW v"and 2W. 'A pail of in'i sulated joints 4 and 5 is provided 'in each end of track 3T. Joint Il of 'each 'of these pairs lis located in the frog side of track 3T between the rails of the adjacent `main track, and ljoint '5 of each pair is located in the 'other si'cl'e of the ilross over track adjacent the heel of the switch at'that end of track 3T.

Track IT is divided yinto 'sections by insulated joints t. A track circuit is provided for track IT including `a suitable source 'of `current such, for example, as a battery l connected across the rails adjacent a given end of one of the two sections shown, `and 'a track relay designated 'by the reference character R connected across the 'rails ad jacent the opposite end of the other section, and also including contacts 8 and II of a stick `relay TS and contacts 9 `and I0 of a slow .pick-up relay NTS, through which the two sections are interconnected.

A track circuit is .provided for track l3T including a suitable scurceof current such, for example, as a battery I2, a track relay 3R, and lfront rconftacts I ll, I5, Il and I8 of a slow release relay designated by the reference character XS.

Stick relay TS h-as a pick-up 'and a stick circuit, both controlled by contacts 2| vand 24 of switch IW and by contacts 2B and 25 of switch 2W. The pick-up circuit for relay TS is also controlled by contact 22 of rel-ay 3R.

Relay XS is controlled by the back point of contact 23 of relay TS, and by the contacts of switches IW and 2W.

Relay NTS is controlled by a back contact 28 of relay XS, and by the front point of contact 23 of relay TS, and also by the contacts of switches IW and 2W.

Contacts 21 an-d 2-8 of relays TS and NTS, respectively, are included in a sign-al control circuit for track 2T, whereas contact 29 of relay R is inclu-ded in a signal con-trol circuit for track IT. Track 2T may also be provided with a track circuit similar to the track circuit 'shown for track IT. The signal control circuit for track 2T would then include a contact ci' the track relay for track 2T instead of including the contacts f relays TS .and NTS. On the other hand, the signal control circuit for track IT, 'as well las the signal control circuit for track 2T,- could include contacts of relays TS and NTS, and contacts 8 and I I of relay TS and contacts 9 and Ill of relay NTS could then be omitted from the track circuit for track IT.

Referring next to Fig. 2, a stretch of railway is here also shown comprising two main tracks designated -by the refer-ence characters IT and 2T connected with each other by a crossover track, designated by the reference character 3T, through hand-operated switches IW an-d 2W. A pair of insulated joints 4 and 5 is provided in each end of track 3T as in Fig. 1, with each insulatecl joint 5 nearer than the yassociated joint 4 to the heel of the adjacent switch. Track 3T is divided into two Isections by a pair of insulated joints 6.

A track circuit is provided for each of these sections, each including a suitable source of current such, for example, as' a battery 'I connected across the rails adjacent the pair of insulated joints 6, and a track relay, designated by the reference character R with a distinguishing pre- X, connected through contacts of the associated switch across the rails adjacent the pair of insulated joints 4 and 5 at the other end of the section. The effective pick-up length of each track circuit section is increased to the location of its insulated joint 5 by a back contact 32 of its track relay connected around its insulated joint 4.

Contacts of track relays IR and 2R are included in signal control circuits for tracks IT and 2T.

As usual, the switch rails at opposite ends of the crossover track 3T, shown in each of the Figs. 1 and 2, are connected by suitable means, shown for example as conductors 43, with the adjacent track rails.

Having described, in general, the arrangement of the various parts o-f apparatus embodying my invention, I shall now describe the circuits and operati-on in detail.

As'slio'wn in the drawings, al1 parts of the apparatus are in the normal condition, that is, each of the switches IW and 2W is in the normal position for a train movement along main track IT or 2T, respectively; each of the relays R, IR, 2R, TS and NTS is energized; relays 3R and XS are deenergized; yand the relay contacts shown in the signal control circuits are closed.

In Fig.' 1, the circuit by which track relay R is energized 'passes from the positive terminal of battery 1, valong rail I a of track IT, front point of contact 8 of relay TS, front point of contact 9 of relay NTS, rail I b of track IT, winding of relay R, rail Ia of track IT, front point of contact I0 of relay NTS, fron-t point of contact Il of relayl TS, and rail Ib of track IT back to battery 1. Relay TS is energized by a stick circuit passing "from asuitable source of current such, for example, as a battery I9, through contact of switch 2W elo-sed in the normal position, contact 2| of switch IW closed in the normal position, frontpoint of contact 2,3 of relay TS, winding of relay TS, contact 24 ofswitch IW closed in the normal position, :and contact 25 of switch 2W back to battery I9. The circuit by which relay NTS is energized passes from battery I 9, through contacts 20 and 2I of switches 2W and IW, respectively, front point of contact 23 of rel-ay TS, back` contact 2:6 of relay XS, winding of relayl NTS, and contacts 24 and 25 of switches IW and 2W, respectively, back to battery I9.

I shall assume that, with apparatus arranged as shown in Fig. 1, a trainman reverses switches 4 IW and 2W for a train to move over track 3T. Contacts 20, 2I, 24 and 25 of switches IW and 2W will therefore -be operated to the reverse position, thereby opening the control circuits :for relays YTS and NTS and placing .a shunt across these relays which are thereby deenergized. Contacts 8, 9, I0 and I I of these relays in the circuit previously traced for relay R are therefore moved to their back points, causing relay R to be deenergized and open the signal control circuit foitrack IT. lContacts 21 and 218 of relays TS and NTS, respectively, will open the signal control circuit previously described for track 2T. -I shall assume further that, when the train has moved from one of the main tracks to the other over cross-over track 3T, a trainman restores switches IW and 2W to the normal position shown in Fig. 1. Relay X'S will thereupon become energized by a circuit passing from battery I9, through contacts 20 and 2I of switches 2W and IW, respectively, back point of contact 23 of relay TS, winding of rel-ay XS, and contacts 24 and 25 of switches IW and 2W, respectively, back to battery I9. With relay XS energized, a track circuit will be completed for energizing relay 3R, this circuit passing vfrom battery I2, through a resistor I3, contact I4 of relay XS, rail 3b of track 3T, contact I5 of rel-ay XS, rail 3b of track 3T, a resistor I6, winding of relay 3R, contact I'I of relay XS, rail 3a of track 3T, contact I8 of relay XS, and rail 3a of track 3T, back to -battery I2. relay TS will become energized by its pick-up circuit which is the same as the stick circuit previously traced yfor this relay except that it includes contact 22 of relay 3R instead of the front point of contact 23 of relay TS. The stick vcircuit for relay TS will then again become closed. With contact 23 of relay TS now open at its back point, relay XS will again be ydeenergized. With rel-ay XS deenergized, the circuit previously traced for relay NTS will again be closed. With relays TS and NTS now energized, the circuit previously traced for relay R will again be closed at the contacts 8, 9, III and II of these relays, and contacts 21 and 28 of relays 'IlS and NTS will now again be closed in the signal control circuit for track 2T,

In Fig. 2, the circuit by which relay IR is energized passes from battery 1, through rail 3b of track 3T, contact 30 of switch IW closed in the normal position, winding of relay IR. contact 3l of switch IW closed in the normal position, and rail 3a of track 3T back to battery 1. Relay 2R is energized by a similar circuit.

I shall assume that, with the apparatus arranged as shown in Fig. 2, a trainman reverses switch IW, causing contacts 30 and 3| of this switch to be open in the normal position and closed in the reverse position, thereby putting a shunt on relay IR, and causing relay IR to be deenergized. =With relay IR deenergized, contacts 34 and 36 shown in the signal control circuits for tracks IT and 2T will be opened. Also. with relay IR deenergized, a path will be completed around insulated joint 4, through back contact 32 of relay IR.

I shall assume that now a car or other vehicle having a short wheel base is left standing on track 3Tbetween insulated joint 4 and the switch point, with at least one pair of wheels between insulated joints 4 and 5, and that a trainman then returns switch IW to its normal position shown inthe drawing. The circuit previously traced for relay IR will again Ybe closed, but relay With relay 3R thus energized,

iR. will. not. pick: up', because. of' being; shunted by a path passing fromv rail. 3b. of. track 331', through at least one. pair of: wheelsand one axle of the; car, raila of track 3T, contact 32 of relay IR, contact 3i of: switch (W, winding of relay 1R, and contact 30 oi switch IfW back to rail. 3b of; track 3T'.

It follows that the effective pick-up length of the track circuit for relay IR. is extended to insulated joint by the. connection around insu;-

lated joint 4 through contact. 32 of relay fR. It will also be noted that a track circuit for track I'I would be shunted by the closing of contact 32 of relay IR around insulated joint in a. circuit path including the upper rail of track 1T, as' shown. in Fig. 2, conductor 43 adjacent switch IW, rail 3a of track 3T, contact 3'2 of relayk IR, rail 3a of track 3T, and the lower rail of track IT, as shown in Fig.,2.

Although I have herein shown. and described'. only a few forms of apparatus embodying my invention, it is understood that variousV changes. and modifications may be made therein within the` scope ofthe appended claims without departingI from the spirit and scope of' my invention.

Having thus described my invention, what I claim is:

1. In trafc protection apparatus i'or a stretch of railway track adjacent a switch operable to a normal and reverse position, the combination comprising, a track relay, an auxiliary relay, a track circuit including the control winding of said track relay and the rails of said stretchv as well as a irontv contact. oi said. auxiliary relay and means for energizingr said track circuit, a. back contact which becomes opened. in response to energization oi said track. relay when said switch is operated from its reverse position to its normal position, and a control circuit for said. auxiliary relay including said back contact and. also. including contact. means closed onlyif said switch is in its normal position.

2. In traffic protection apparatus. for a stretch of railway track adjacent a switch operable. to a normal and a reverse position, the combinationv comprising, a track relay, an auxiliary relay, a track circuit including the control winding of said track relay and controlled by a iront contact of said auxiliary relay, a backv Contact controlled by said track relay to become opened when said track relay .becomes energized, and a control circuit for said auxiliary relay controlled by said back contact and by Contact means closed only if said switch is in its normal position.

3. In traido protection apparatus. for a stretch of railway track adjacent a switch operable to a normal and a reverse position, the combination comprising, a track relay, an auxiliary relay, a

track circuit including the control winding of said track relay and controlled by a front contact of said auxiliary relay, a back contact con,- trolled to become opened in response to energizetion of said track relay when said switch is oper ated to its normal position, and control means for said auxiliary relay including said back contact.

4. In traic protection apparatus for a stretch of railway track adjacent a switch operable to a iirst and a second extreme position, the combination comprising, a track relay, a contact which becomes opened in response to energization of said track relay when said switch is operated to said iirst position from said second position, a track circuit including the rails of said stretch and the control element of said track relay, and

means including saidcontact for" controlling said track circuit.

5'. In tramo protection apparatus for a stretchy of' railway track'. adjacent; a switch operable toa first and. a` second extreme position, the combination comprising, a. track relay, a stick relay, aslow release:y relay, a slow pick-up relay, a trackcircuit including the rails of; said stretch and the control elementof. said trackv relay and controlled byv front' contact means: of said slow release relay, a. pick-up circuit forl said stick. relay controlled by said'. switch in its` first position and. by a iront contactr of said track relay, a stick circuit for said stick relay controlled by said switch in its rst position, a circuit controlled by said. switch in its rst` position and by a back contact of said stick relay for controlling said slow release relay, and a circuit controlled. by said switch in its first position and. by' a` front contact of said stick relay and also by a back contact oi said slow re lease relay for-controlling said slow pick-up relay.

6. In traffic protection apparatus for a stretch ci" railway track adjacent a switch operable. to a rst and a second extreme position, the combination. comprising, a track relay, a stick relay, a slow release relay, a. track circuit including the rails of said stretch. and the control element of said track relay and' controlled by front contact' means of said slow releasev relay, a pick-up circuit for said stick relay controlled by said switch in its. first position and by a front contact of said track relay, av stick circuit for said stick relay controlled oy said switch in its first position, and a circuit controlled byv said switch in its first position and by a back contact, of said stick relay for controlling said slow release relay.

'7. In traic protection apparatus for a stretch of railway track adjacent a switch operable to a iirst and a second extreme position, the combination comprising, a track relay, a contact which becomes opened inresponse to energization of said track relay when said switch is operated to said first position from said second position, a track circuit for controlling said track relay responsive toV av train on said stretch of track, and means including said contact for controlling said track circuit.

8. In traffic protection apparatus for a stretch of railway track adjacent .a switch operable to a rst and a second extreme position, the combination comprising, a track relay, a Contact which becomes opened in response to energization of said track lrelay when said switch is operated to said first` position from ysaid second position, a track circuit for controlling said track relay responsive to.k a train on said stretch of track, and means including said contact for effecting energization of said relay by said track circuit when said switch is operated from its second position to its rst position if said stretch of track is unoccupied.

9. In traiiic protection apparatus for a stretch of auxiliary track connected with a main track by a switch operable to a first and a second extreme position, the combination comprising, an insulated joint in the frog side of said auxiliary track between the rails of said main track, a track relay, a track circuit including the rails of said stretch of auxiliary track for energizing said track relay, a second insulated joint in the other side of said auxiliary track adjacent the heel of said switch for insulating one side of said track circuit from said main track, and a contact which becomes opened in response to energization of said track relay when said switch is operated to said rst position from said second position; said track circuit including at least a part of a circuit path connected with said frog side of said auxiliary track on opposite sides of said rst insulated joint and completed when said contact is in its closed condition, and which path when completed also serves to provide a shunt path from rail to rail of said main track.

10. In traffic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track, the combination comprising, a pair of insulated joints in each end of said crossover track one joint of each of said pairs located between the rails of the adjacent main track and the other joint of each of said pairs located in the other side of said crossover track adjacent the heel of the corresponding switch, a slow release relay, a track relay, a track circuit for said crossover track including a source of energy connected through a front contact of said slow release relay across the rails adjacent the heel of one of said switches and including said track relay connected through a second front contact of said slow release relay across the rails adjacent the heel of the other switch and also including a third front contact of said slow release relay connected around the insulated joint between the rails of one main track and a fourth front contact of said slow release relay connected around the insulated joint between the rails of the other main track, a stick relay, a pick-up and a stick circuit for said stick relay each controlled by said switches in the normal position and the pick-up circuit also controlled by a front contact of said track relay, and a control circuit for said slow release relay controlled by a back contact of said stick relay.

11. In traffic protection apparatus for a stretch of railway in which two main tracks are interconnected by a crossover track, the combination comprising, a ,pair of insulated jointsl in each end of said crossover track one joint of each of said pairs located between the rails of the adjacent main track and the other joint of each of said pairs located in the other side of said crossover track adjacent the heel of the corresponding switch, a slow release relay, a track relay, a track circuit for said crossover track including a source of energy connected across the rails adjacent the heel of one of said switches and said track relay connected across the rails adjacent the heel of the other switch and also including a front contact of said slow release relay connected around the insulated joint between the vrails of one jmain track and a second front contact of said slow release relay connected around the insulated joint between the rails of the other main track, a stick relay, a pick-up and a stick circuit for said stick relay each controlled by said switches in the normal position and the pick-up circuit also controlled by a front contact of said track relay, and a control circuit for said slow release relay controlled by a back contact of said stick relay.

12. In tralc protection apparatus for a stretch of auxiliary track connected with a main track by a switch, the combination comprising, a pair of insulated joints in said auxiliary track one of said joints in the frog side between the rails of said main track and the other one of said joints in the other side of said auxiliary track nearer than said rst joint to the heel of said switch, a track relay, a track circuit including the rails of said auxiliary track extending between said pair of insulated joints and a given point in the opposite direction from the frog of said switch andalso including the control winding of said track relay connected through contact means closed when said switch i's in a given position, and a back contact of said track relay connected around the insulated joint in the frog side of said auxiliary track.

13. In traiic protection apparatus for a stretch of auxiliary track connected with a main track by a switch, the combination comprising, a pair of insulated joints in said auxiliary track one of said joints in the frog side between the rails of said main track and the other one of said joints in the other side of said auxiliary track nearer than said first joint to the heel of said switch, a track relay, a track circuit including the rails of said auxiliary track extending between said pair of insulated joints and a given point in the opposite direction from the frog of said switch and also including the control winding of said track relay, and a back contact of said track relay connected around the insulated joint in the frog side of said auxiliary track.

14. In trac protection apparatus for a stretch of auxiliary track connected with a main track by a switch, the combination comprising, a track relay, a track circuit including the control winding of said track relay for said auxiliary track adjacent said switch normally deenergized while said switch is in the normal position for traic movements along said main track, a contact controlled to become opened in response to energization of said track relay when said switch is operated to its normal position, and means including said contact for effecting energization of said track circuit for a brief period of time when said switch is restored from its reverse position to said normal position.

LOWELL B. YARBROUGH.

REFERENCES CITED The following references are of record in the file of this patent:

A UNITED STATES PATENTS Number 

